Ep. 15: Hajime uncovers the killer's identity amidst a cavern collapse and treasure burial.

15

Hajime deduces that the red torii appears black due to a geyser, while Hisayoshi Yaogi locates the treasure but is found dead. Hajime identifies the killer as Koichiro Saeki, who disguised himself as Midori Mimasaka to avenge his father. Inside the cavern guarded by a Yamawara statue, former butler Eisaku Iwata attempts to kill the group to keep the gold. Kyoko Kaya, a police officer investigating Iwata for murder and fraud, shoots him. Iwata’s attempt to seize the gold topples the statue, killing him and collapsing the cavern. Hajime saves Koichiro, who explains his love for Midori and her subsequent suicide. Koichiro is arrested, and the contents of Kyoko Kaya’s box remain unknown.